Functional recovery of Amazonian bat assemblages following secondary forest succession

Regenerating forests occupy large areas in the tropics, mostly as a result of deforestation for livestock and agriculture, followed by land abandonment. Despite the importance of regenerating secondary forests for tropical biodiversity conservation, studies of temporal effects of matrix regeneration on species responses in fragmented landscapes are scarce. Here, we used an Amazonian whole-ecosystem fragmentation experiment to investigate how changes in matrix quality over time through secondary forest regeneration affect bat assemblages from a functional perspective. We found that forest regeneration in the matrix positively affected functional α diversity, as well as species- and community-level functional uniqueness, reflecting an increase of species that perform different ecological functions in secondary forest over time. According to functional trait composition, animalivorous species showed the clearest signs of recovery associated with matrix regeneration. Consequently, between-period differences in functional β-diversity were highest in secondary forest compared to fragments and continuous forest, determined mainly by trait gains. However, ~ 30 years of secondary forest regeneration were not sufficient for the functional recovery of bat assemblages to levels observed in continuous forest. Restoring degraded habitats while protecting primary forest will be an important strategy for safeguarding high functional diversity of bats and their vital contributions to ecosystem functioning in fragmented tropical landscapes

The road to functional recovery : temporal effects of matrix regeneration on Amazonian bats

Across the tropics, vast deforested areas are undergoing forest regeneration due to land abandonment. Although secondary forest is an expanding type of landscape matrix that has been shown to buffer some of the negative consequences of forest loss and fragmentation on taxonomic diversity, little is known in this regard about the functional dimension of biodiversity. We took advantage of an ecosystem-wide fragmentation experiment to investigate longer term changes in functional diversity of a mega-diverse Amazonian bat assemblage associated with regrowth development in the matrix. We found that matrix regeneration affected several facets of bat functional diversity in secondary forest over time, increasing functional α diversity, species- and community-level functional uniqueness, altering functional trait composition, and resulting in functional β-diversity changes via trait gains. However, approximately 30 years of matrix regeneration were insufficient for functional diversity to recover to the same levels as in continuous forest. Our results suggest that a combination of natural, human-assisted, and active restoration is likely to be the most successful strategy for restoring functional biodiversity of bats in human-modified tropical landscapes, a finding that most likely also applies to many other taxa

Design matters : an evaluation of the impact of small man-made forest clearings on tropical bats using a before-after-control-impact design

In recent years, large clearings (>1000 ha) accounted for gradually smaller amounts of total annual deforestation in the Brazilian Amazon, whereas the proportion of small clearings (<50 ha) nowadays represents more than 80% of annual deforestation. Despite the ubiquity of small clearings in fragmented Amazonian landscapes, most fragmentation research has focused on the effects of large-scale deforestation, leading to a poor understanding of the impacts of smaller barriers on Amazonian vertebrates. We capitalized on the periodical re-isolation of experimental forest fragments at the Biological Dynamics of Forest Fragments Project in the Central Amazon as a before-after-control-impact experiment to investigate the short-term effects of small clearings on bat assemblages. Over the course of three years we sampled six control sites in continuous forest, the interiors and edges of eight forest fragments as well as eight sites in the surrounding matrix. Sampling took place both before and after the experimental manipulation (clearing of a 100 m wide strip of regrowth around each fragment), resulting in ~4000 bat captures. Species were classified as old-growth specialists and habitat generalists according to their habitat affinities and a joint species distribution modeling framework was used to investigate the effect of fragment re-isolation on species occupancy. Following fragment re-isolation, species richness declined in all habitats other than fragment edges and, although responses were idiosyncratic, this decline was more pronounced for forest specialist than for generalist species. Additionally, fragment re-isolation led to a reduction in the similarity between assemblages in modified habitats (fragment interiors, edges and matrix) and continuous forest. Sampling of controls in continuous forest both prior to and after reisolation revealed that much of the variation in bat species occupancy between sampling periods did not arise from fragment re-isolation but rather reflected natural spatiotemporal variability. This emphasizes the need to sample experimental controls both before and after experimental manipulation and suggests caution in the interpretation of results from studies in which the effects of habitat transformations are assessed based solely on data collected using space-for-time substitution approaches

Design matters : an evaluation of the impact of small man-made forest clearings on tropical bats using a before-after-control-impact design

In recent years, large clearings (>1000 ha) accounted for gradually smaller amounts of total annual deforestation in the Brazilian Amazon, whereas the proportion of small clearings (<50 ha) nowadays represents more than 80% of annual deforestation. Despite the ubiquity of small clearings in fragmented Amazonian landscapes, most fragmentation research has focused on the effects of large-scale deforestation, leading to a poor understanding of the impacts of smaller barriers on Amazonian vertebrates. We capitalized on the periodical re-isolation of experimental forest fragments at the Biological Dynamics of Forest Fragments Project in the Central Amazon as a before-after-control-impact experiment to investigate the short-term effects of small clearings on bat assemblages. Over the course of three years we sampled six control sites in continuous forest, the interiors and edges of eight forest fragments as well as eight sites in the surrounding matrix. Sampling took place both before and after the experimental manipulation (clearing of a 100 m wide strip of regrowth around each fragment), resulting in ~4000 bat captures. Species were classified as old-growth specialists and habitat generalists according to their habitat affinities and a joint species distribution modeling framework was used to investigate the effect of fragment re-isolation on species occupancy. Following fragment re-isolation, species richness declined in all habitats other than fragment edges and, although responses were idiosyncratic, this decline was more pronounced for forest specialist than for generalist species. Additionally, fragment re-isolation led to a reduction in the similarity between assemblages in modified habitats (fragment interiors, edges and matrix) and continuous forest. Sampling of controls in continuous forest both prior to and after reisolation revealed that much of the variation in bat species occupancy between sampling periods did not arise from fragment re-isolation but rather reflected natural spatiotemporal variability. This emphasizes the need to sample experimental controls both before and after experimental manipulation and suggests caution in the interpretation of results from studies in which the effects of habitat transformations are assessed based solely on data collected using space-for-time substitution approaches

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202

FragSAD : A database of diversity and species abundance distributions from habitat fragments

Habitat destruction is the single greatest anthropogenic threat to biodiversity. Decades of research on this issue have led to the accumulation of hundreds of data sets comparing species assemblages in larger, intact, habitats to smaller, more fragmented, habitats. Despite this, little synthesis or consensus has been achieved, primarily because of non-standardized sampling methodology and analyses of notoriously scale-dependent response variables (i.e., species richness). To be able to compare and contrast the results of habitat fragmentation on species' assemblages, it is necessary to have the underlying data on species abundances and sampling intensity, so that standardization can be achieved. To accomplish this, we systematically searched the literature for studies where abundances of species in assemblages (of any taxa) were sampled from many habitat patches that varied in size. From these, we extracted data from several studies, and contacted authors of studies where appropriate data were collected but not published, giving us 117 studies that compared species assemblages among habitat fragments that varied in area. Less than one-half (41) of studies came from tropical forests of Central and South America, but there were many studies from temperate forests and grasslands from all continents except Antarctica. Fifty-four of the studies were on invertebrates (mostly insects), but there were several studies on plants (15), birds (16), mammals (19), and reptiles and amphibians (13). We also collected qualitative information on the length of time since fragmentation. With data on total and relative abundances (and identities) of species, sampling effort, and affiliated meta-data about the study sites, these data can be used to more definitively test hypotheses about the role of habitat fragmentation in altering patterns of biodiversity. There are no copyright restrictions. Please cite this data paper and the associated Dryad data set if the data are used in publications.Peer reviewe